Effect of some traditional processing operations on the functional properties of African breadfruit seed (Treculia africana) flour

The effect of germination, fermentation, roasting and defatting on the proximate composition, water absorption capacity (WAC), oil absorption capacity (OAC), foaming capacity (FC), foaming stability (FS), emulsion capacity (EC), emulsion stability (ES), packed bulk density (PBD), least gelation concentration (LGC) and protein solubility (PS) of breadfruit seed flour (BSF) was investigated. WAC, OAC, FC, EC, PBD and LGC obtained are 190-380%; 130.3-200.5%; 2.3-60.4%; 12.4-52.9%; 0.4-0.6 g/ml; 6-12% (w/v) and 200-420%; 176.4-320.6; 4.2-70.8%; 20.2-60.4%; 0.5-0.7 g/ml; 0.5-0.8% (w/v) in the full fat and defatted flours respectively. Foams were more stable in the untreated; least in fermented and roasted samples. Defatting improved the FC, FS and EC; roasting and fermentation reduced EC of full fat BSF; Processing and defatting had no effect on the PBD; roasting and germination increased LGC while defatting and fermentation reduced it. Full fat flours had the lowest PS at pH 4 and the highest at pH 8. Fermented full fat BS flour had the highest PS at pH 5 and 8. Defatted germinated, raw dried and roasted BSF had lowest PS at pH 4; PS of fermented BSF is lowest at pH 3 and highest at pH 2.     

Quality evaluation of beef patties formulated with bambara groundnut (Vigna subterranean L.) seed flour

This study evaluated composite beef–bambara groundnut (Vigna subterranean L.) seed flour patties to determine the effect of bambara groundnut flour (BGF) inclusion on the quality and acceptability of the products. The effect of different levels of BGF (0%, 2.5%, 5.0% and 7.5%) on the proximate composition and pH indicate that BGF had no significant (p ? 0.05) effect on moisture, protein and carbohydrate of raw patties except ash and pH whereas there was significant (p ? 0.05) effect on all the parameters for the cooked patties. BGF significantly (p ? 0.05) reduced the shrinkage of the cooked patties from 9.13% to 6.76%, while percentage cooking yield, moisture retention, and fat retention increased significantly (p ? 0.05) with increasing BGF levels from 79.1% to 87.2%, 67.51% to 78.05% and 73.51% to 88.34%, respectively. The use of BGF significantly (p ? 0.05) increased the pH of cooked patties from 6.16 to 6.23. Beef patties extended with BGF up to 5% addition exhibited good quality attributes most acceptable to the consumers. The pH of the 0% BGF–beef patties decreased significantly during storage, up to day 14, and increased thereafter. However, the pH of the patties with BGF consistently decreased significantly up to day 21. The TBA values of both (0% and 5% BGF–beef patties) increased significantly (p ? 0.05) from 0.054 to 0.25 and from 0.05 to 0.24 mg malonaldehyde/kg, respectively. All sensory attributes decreased significantly (p ? 0.05) as storage time progressed. The physico-chemical, microbiological and sensory characteristics of the patties were found to be acceptable after 21 days refrigerated storage.     

Functional Properties of Raw and Heat Processed Winged Bean (Psophocarpus tetragonolobus) Flour

Nitrogen solubility, emulsification capacity, foam capacity, fat and water absorption capacity of raw and heat-processed winged bean flour were compared with those of raw soy flour, both as a function of pH and NaCl concentration. Nitrogen solubility vs pH profile showed only one minimum, at pH 4.5. Heat processing of winged bean flour lowered nitrogen solubility. Water and fat absorption capacity of winged bean flour were 2.1 g/g and 1.4 g/g, respectively; those of raw soy flour were 3.1 g/g and 1.2 g/g. Heat processing increased water and fat absorption capacity of winged bean flour by 38% and 57%, respectively. Emulsification capacity of raw winged bean flour was higher than that of raw soy flour by about 30–60% depending on the pH. Heat processing diminished emulsification and foam capacity of winged bean flour by about 35% and 18%, respectively. Incorporation of NaCl up to 0.4M improved emulsification capacity of winged bean flour and foam capacity up to 0.2 M.     

Use of low-temperature extrusion for reducing phytohemagglutinin activity (PHA) and oligosaccharides in beans (Phaseolus vulgaris L.) cv. Navy and Pinto

Bean (Phaseolus vulgaris L.) lectins and oligosaccharides are the anti-nutrients that limit dry bean consumption. The objective of this study was to study the effects of low temperature (85 °C) extrusion and steam-cooking (82 °C) on the fate of lectin, analysed as phytohemagglutinin activity (PHA), and the oligosaccharides, raffinose and stachyose. Both extrusion processing and steam-cooking significantly (p ? 0.05) reduced the lectin in bean flour by 85–95% over raw bean flours (control). The stachyose content in extruded navy bean flours was comparable to that in raw and steam-cooked flours while extruded pinto bean flour had significantly lower stachyose content than that found in raw and steam-cooked flour. The raffinose content of both navy and pinto extruded flours, though lower than raw bean flours, was significantly higher than that in steam-cooked flours. The results of this study demonstrated that extrusion processing at relatively lower temperature can be effective in eliminating lectins and reducing oligosaccharides.     

Exploitation of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours: Chemical characterization and their use for sourdough fermentation

This study aimed at characterizing the chemical and microbiological composition of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours and at exploiting their potential for sourdough fermentation. Both the flours had a gross composition similar to other cereals. As shown by two-dimensional electrophoresis analysis, Acha flour had a higher number of prolamins with respect to Iburu flour. The opposite was found for the number of glutelin spots. The concentration of total free amino acids of Iburu flour was higher than that of Acha flour (1348 ± 34 vs. 100 ± 20 mg/kg). Pediococcus pentosaceus was the dominant species in both the flours. Several isolates were used to ferment Acha or Iburu flours. After 8 h fermentation at 30 °C, pH ranged from 3.41 to 3.83 and from 4.20 to 4.66 for Acha and Iburu sourdoughs, respectively. The highest values of TTA and concentration of lactic acid were found in almost all Iburu sourdoughs. The synthesis of acetoin and γ-amino butyric acid (GABA) was only found in Iburu sourdoughs. Data from the kinetics of acidification, synthesis of lactic and acetic acids, acetoin, and liberation of total free amino acids were elaborated by Principal Component Analysis. Sourdoughs from Acha and Iburu flour were clearly differentiated.     

Evaluation of the performance of flours from cross- and self-pollinating Canadian common buckwheat (Fagopyrum esculentum Moench) cultivars in soba noodles

Two Canadian cross-pollinating common buckwheat (Fagopyrum esculentum Moench) varieties, Koban and Koto, and two self-pollinating lines, BR01 and BR06, were dehulled and roller milled on a pilot mill to produce three distinct milled products, white flour, dark flour and whole groat flour. The white flours contained mostly starch (79.2–87.2%), whereas the dark flours were rich in proteins (37.1–38.7%), dietary fibre (15.2–22.0%), ash (5.49–5.99%), and fagopyritols (1420–2220 mg/100 g). The buckwheat flours were blended with wheat flour (Canada Western Red Spring straight grade flour) at 60:40 ratios and evaluated for soba noodle properties. Significant differences in milling properties, and in raw noodle colour and texture were detected among cultivars, although the impact of flour type on noodle properties was far greater. The self-pollinating lines exhibited comparable milling and soba noodle properties to Koban. Koto exhibited slightly higher white flour yield and generally firmer noodle texture compared to the other lines. White flours produced the brightest noodles, followed by whole groat and dark flours. Dark flours yielded the thickest cooked noodles with the largest maximum cutting stress and greatest resistance to compression. Noodles prepared with white flour offered the best chewiness, springiness and recovery parameters. Soba noodles prepared with dark flours contained considerably higher amounts of minerals, proteins, dietary fibre, and fagopyritols than noodles prepared with white flour.     

Gelation,thermal and pasting properties of pigeon pea (Cajanus cajan L.), dolichos bean (Dolichos lablab L.) and jack bean (Canavalia ensiformis) flours

This study evaluated the rheological, thermal and pasting properties of pigeon pea (PP), dolichos bean (DB) and jack bean (JB) legume flours and gels. Starch and protein contents were also measured and its molecular weight distribution was determined by electrophoresis. PP and DB showed the highest viscosities while JB had the highest pasting temperature. The minimum flour concentrations for gel formation were estimated at 6–8% for DB and PP and 10% for JB. Above these concentrations all flour suspensions heated to 95 °C led to gels with a solid-like behavior. Differential scanning calorimetry showed two endothermic peaks in all flours at 80–89 °C and 96–100 °C. Avrami model was successfully fitted to the hardening kinetics of PP and DB gels stored at 4 °C. The half-life times were 22 and 6 h for PP and DB respectively. PP and DB flours were able to form self-supporting gels and could be applied in the formulation of gel-like foods.     

Nitrogen extractability and functional properties of defatted Erythrina variegata flour

Defatted Erythrina variegata flour was prepared from dehusked seed meal by hexane extraction of residual oil. The resulting flour had 403 g kg⁻¹ of protein as compared to 282 g kg⁻¹ in the whole seed-defatted meal. Nitrogen extractability of the defatted flour in water was not much influenced by the length of extraction period above 40 min, but an increased extraction was observed at a higher liquid to solid ratio up to a studied limit of 1:60; the optimal ratio was found to be 1:30. The minimum of 26.9% nitrogen was extracted in the pH range 3.0–4.0 and maximum of 94.8% at pH 12. Addition of sodium chloride (0.1 or 0.5 M) broadened the pH range of minimum nitrogen extractability and shifted it toward a lower pH region. At both concentrations of sodium chloride, a marked increase in nitrogen extractability, in the pH range 3.0–7.0, was observed. Precipitation of protein from an extract of pH 10.0 was maximum (85.3%) at pH 4.75. A higher buffer capacity of the flour was observed in the acidic medium (0.195 mmol HCl g⁻¹ flour) than in alkaline medium (0.093 mmol NaOH g⁻¹). Water absorption and oil absorption values for the whole E. variegata seed flour and the dehusked, defatted flour were 1.81, 1.43 and 1.02, 1.52 kg kg⁻¹, respectively.     

Physical and functional characteristics of selected dry bean (Phaseolus vulgaris L.) flours

Many varieties of dry beans (Phaseolus vulgaris L.) are available with entirely different physico-chemical and sensory characteristics. Selected dry bean varieties (red kidney, small red kidney, cranberry and black) were processed into flour and analyzed for the physico-chemical and functional characteristics. The bulk density of the beans flours varied significantly (p < 0.05) from 0.515 g/ml for black bean flour to 0.556 g/ml for red kidney bean flour. The small red kidney bean flour had the highest water absorption capacity (2.65 g/g flour) while black bean flour showed the lowest at 2.23 g/g flour. Significant differences were observed for oil absorption capacities of bean flours, which ranged from 1.23 g/g for small red kidney bean flour to 1.52 g/g for red kidney bean flour. The bean flours emulsion capacity and stability and foaming capacity and stability also varied significantly and was variety-dependent. The highest apparent viscosity, 0.462 Pa.s, was recorded for small red kidney bean flour whereas black bean flour exhibited the lowest value of 0.073 Pa.s at 30 g/100 ml water content in the flour dispersions. The force-deformation curves for doughs from different bean flours showed that black bean flour had the highest peak force or hardness value of 90.7 N followed by doughs from cranberry, small red kidney and red kidney bean flours. The results of this study offer useful data on bean flours' potential uses in different food products.     

Nutritional quality evaluation of electron beam-irradiated lotus (Nelumbo nucifera) seeds

Nutritional and antinutritional qualities, and functional properties of raw and electron beam-irradiated (doses: 0, 2.5, 5, 7.5, 10, 15 and 30 kGy) lotus seeds were studied. Seeds were rich in protein, amino acids, unsaturated fatty acids and minerals, without heavy metal contamination. Irradiation of seeds revealed a decrease in crude protein and fibre, which was not significant at any of the doses. However, significant increase of ash (10 kGy onwards) and carbohydrates (at 30 kGy) were recorded after irradiation. Seed flours showed a significant dose-dependent decrease in water absorption capacity, while oil absorption capacity significantly increased from 10 kGy onwards (p < 0.05). Also, significant increase in protein solubility (5 kGy onwards) and foaming capacity (7.5 kGy onwards) with improvement in the least gelation capacity (5 kGy onwards) of seed flour (p < 0.05) was recorded after irradiation. Electron beam irradiation of seeds resulted in significant dose-dependent elevation of total phenolics and tannins, while phytic acid was eliminated at 5 kGy. Seeds of lotus can serve as food and minimise protein-energy malnutrition of economically weaker sections of the population in developing countries. The seed flours also possess great potential for development of new food products and formulations. As a physical method of preservation, electron beam irradiation was effective in the retention of the nutritional qualities of lotus seeds and is recommended for commercial exploitation.     

Thermal processing effects on the functional properties and microstructure of lentil, chickpea, and pea flours

Pulses are rich in nutrients. The existence of anti-nutritional components and the length of time required for preparation have, however, limited their frequency of use compared to recommended intake levels. Anti-nutritional components in pulses can be largely removed by heat treatment. Additionally pre-treatment of pulses with heat and processing of seeds into flour could further enhance their use by decreasing processing and preparation times. In this study, trypsin inhibitor activity, functional properties, and microstructural characteristics of flours prepared from different varieties of lentil, chickpea, and pea as affected by roasting and boiling were evaluated. Both thermal treatments resulted in significant reduction (p < 0.05) in trypsin inhibitor activity ranging from − 95.6% to − 37.8%. Scanning electron microscopy (SEM) results showed that the roasted pulse flours had similar microstructure (i.e., starch granule and protein matrix structure) to the raw samples. For the pre-boiled flours, amorphous flakes were observed by SEM with no presence of intact starch granules. This is likely due to gelatinization of starch during cooking. Interestingly, flours treated by boiling exhibited significantly higher (p < 0.05) fat binding capacity, water holding capacity, and gelling capacity, while protein solubility was significantly reduced compared to the raw and roasted pulse flours. Overall, thermal treatments either had no impact or impacted to different extents the emulsifying and foaming properties of the flours. Our results suggest that thermally-treated pulse flours may have very good potential to be used as value-added food ingredients for food applications due to their improved nutritional value and, in some instances, superior functionality.     

Studies on bambara groundnut flour performance in Okpa preparation

Bambara groundnut flours of different particle sizes were prepared after bean seeds had been cold‐soaked and/or germinated, dried, milled and sieved. The flours were used to prepare okpa (local dish prepared by steaming mashed bambara groundnut) and their sensory properties determined. Viscosity of the flour pastes, before steaming, were also determined. Results showed that bambara groundnut flours from both germinated and cold‐soaked beans could be used in preparing good quality okpa and, therefore, remove all the problems involved in preparing the raw beans for okpa‐making as is done traditionally. Particle size appeared to play a major role in obtaining good okpa; therefore flours intended for okpa preparation should be such that 66, 86 and 96%, respectively, of cold‐soaked bean flour or 58, 78 and 91%, respectively, of germinated bean flour, after 1, 3 and 5 milling passes, should be in the particle range 1.5–4.5 × 10^?4 m. Slightly higher amounts of the coarse (6.0 × 10^?4 m) particles are needed in the germinated bean flours to compensate for the breakdown of starch and proteins, the gelling agents in bambara groundnut. Copyright © 2004 Society of Chemical Industry     

Functional and electrophoretic characteristics of faba bean (Vicia faba) flour proteins as affected by germination

Faba beans (Vicia faba) were germinated at room temperature for 3 and 6 days respectively. The effect of germination on the protein fractions, protein solubility index, PAGE pattern and some functional properties i.e. emulsification capacity (EC), foaming capacity (FC), foam stability (FS), water and fat absorption capacities of the flour was studied. Germination decreased albumins, globulins and prolamins at different levels but non protein nitrogen and glutelins were increased. The protein solubility index was high at both extreme pH values with an isoelectric point (IP) at pH of 4.4-4.5. The solubility of the protein slightly increased due to germination at all the pH values. PAGE pattern revealed on obvious dissociation and utilization for both fast and slow moving protein fractions during germination. Emulsification and foaming properties vs pH profile were similar to the pattern of solubility vs pH. Both properties were high at acidic and alkaline pH's and the minimum values were at pH 4 to 5. Germination process improved EC, FC and FS of the flour in comparison with that of dry bean flour. Water absorption of faba bean flours was improved during germination but the fat absorption markedly decreased.     

Characterisation of phenolic components present in raw and roasted wattle (Acacia victoriae Bentham) seeds

The effect of roasting on the phenolic components of Australian wattle (Acacia victoriae Bentham) seed was investigated. Wattle seeds were roasted at 200 °C for 5–30 min and ground to flour, which were then extracted with 70% acetone. The total phenolic and flavonoid contents of the extracts were determined, and the phenolic components were analysed by reverse phase-high performance liquid chromatography (RP-HPLC) coupled with an on-line post-column reaction system to determine the active antioxidant peaks. The major peaks were then purified by preparative HPLC and identified by gas chromatography–mass spectrometry (GC–MS) analysis. Roasting of wattle seeds resulted in significant increases in its soluble phenolic content. The concentration of total phenolics and flavonoids in the seeds roasted for 30 min was more than nine and four times higher, respectively, than that in the raw seeds. The major phenolic acids present in wattle seeds were found to be succinic and gallic acids, the concentration of which increased by up to 10-fold as a result of roasting.     

In-vitro multienzyme digestibility of protein of some plant source flours blended with bovine plasma protein concentrate

The in-vitro multienzyme protein digestibilities of the flours of maize, cassava, pigeon pea (Cajanus cajan), African yambean (Sphenostylis stenocarpa) and bambara groundnut (Vigna subterranea), blended with bovine plasma protein concentrate were investigated. The multienzyme system consists of trypsin, chymotrypsin and peptidase. It was found that the addition of bovine plasma protein concentrate improved the protein digestibility of the flours compared with flours without the additive. The digestibilities were increased by between 3% in bambara groundnut blended flour to about 10% in cassava blended flour. When the flours were wet-heat treated, the digestibilities further increased in all samples with increments between 7·5 % in bambara groundnut and 16·6% in cassava flour. Bovine plasma protein concentrate may be a good source of protein for the fortification of protein-deficient foods, particularly maize and cassava flours.     

Properties of some citrus seeds. Part 2. Functional properties of seed flours

Water and fat absorption, gelation, protein solubility, emulsification and foam capacities of flours from citron, orange and mandarin seeds were determined. The protein solubility of the flours was increased as sodium chloride concentration increased up to 0.8 M for citron, mandarin and mixture seed flours and 1 M for orange seed flour, then decreased at higher concentrations. The minimum solubility was sharp for mandarin and orange seed flours, while, it was broader for mixture and citron seed flours. The least concentration for forming gel was 6%, 6.5% and 7% for mandarin, orange and both citron and mixture seed samples, respectively. The flours of orange and mandarin seeds were the highest and lowest in water absorption capacity. Also, the highest value of fat absorption capacity was noticed for citron and lastly for mandarin on flour basis. The emulsification and foam capacity-pH patterns were similar to protein solubility-pH profiles for all citrus seed flours. Foam capacity of mandarin and mixture seed flour were lower than that of citron and orange seed flours. The emulsification and foam capacities patterns in sodium chloride solution showed an increase up to 0.6 M and then decreased in all citrus seed flours. Foam stability of citrus seed flours was increased with sodium chloride concentration up to about 0.6 M and then decreased. The foam stability of all citrus seed flours at pH 4.5 was very poor but at pH 2, it was comparable to that at pH 8.     

PROCESSING AND FUNCTIONAL PROPERTIES OF YAM BEANS (SPHENOSTYLIS STENOCARPA)

The proximate and selected functional properties of five flours from yam bean (YB) made after the grains were not processed (raw) and processed as boiled, fermented, roasted and malted, were determined. The functional properties were water and fat absorption, gelation, emulsification and whippability. An improvement was observed for protein content of flours processed beans compared to raw flour. Fermentation improved the oil content of the flour. The emulsifying and foaming capacities (50.7 and 40.20%, respectively) observed for raw flour were significantly higher than those for the flours from processed bean. Gelation was significantly (P < 0.05) increased and decreased by fermentation and malting of the bean, respectively. The water absorption capacities ranged from 131.9% in raw flour to 218.8% in flour boiled beans. There were no significant (P > 0.05) differences in the fat absorption capacities of all flours except for the one of fermented beans (0.40 mL/g), which was significantly lower than the value (0.73 mL/g) obtained for the flour from boiled beans. Although a high foaming capacity was observed for raw flour, it was less stable when compared with that of the processed bean flours. Overall, YB flour was found to exhibit good functional properties, and has a great potential for use as an ingredient in selected food systems.     

Iron fortification of finger millet (Eleucine coracana) flour with EDTA and folic acid as co-fortificants

Fortification of staple foods with iron is a feasible strategy to enhance the intake of this mineral. In the present investigation, finger millet flour was explored for its suitability as a vehicle for fortification with iron. Ferrous fumarate and ferric pyrophosphate were added at levels that provided 6 mg of iron per 100 g of the flour, and both were found to be equally effective. Inclusion of EDTA and folic acid, along with the iron salts, significantly increased the bioaccessibility of iron from the fortified flours. The fortified flours were stable up to a period of 60 days. There was a decline in the bioaccessible iron content in the flour fortified with ferric pyrophosphate after 30 days of storage. Heat processing of the flours improved the bioaccessibility of iron from the unfortified and fortified flours. Fortification with iron did not affect the bioaccessibility of the native zinc from the flours.     

Effect of legume seed extracts on the inhibition of proteolytic activity and muscle degradation of fresh water prawn (Macrobrachiumrosenbergii)

Trypsin inhibitors in the extracts from soybean (Glycine max), adzuki bean (Vigna angularis), bambara groundnut (Vigna subterranea) and red kidney bean (Phaseoulus vulgaris) varied in amount and molecular weight. The soybean extract had the highest level of trypsin inhibitor with molecular weight (MW) of 21 kDa, followed by bambara groundnut extract possessing trypsin inhibitor with MW of 15 kDa. Both extracts showed a more effective inhibition towards crude protease extract (CE) from the hepatopancreas of fresh water prawn (Macrobrachium rosenbergii) than the extracts from adzuki and red kidney beans. Activity staining also reconfirmed the higher inhibitory activity on CE from hepatopancreas by the extracts from both soybean and bambara groundnut. The extracts from all seeds were able to inhibit the degradation of fresh water prawn meat containing CE in a concentration dependent manner. Based on inhibitor study, the extracts from soybean and bambara groundnut can be a potential aid to suppress the muscle softening of fresh water prawn, mediated by trypsin-like proteases released from hepatopancreas, during extended iced storage.     

Functional Properties of Raw and Heat Processed Cowpea (Vigna unguiculata, Walp) Flour

The functional properties, gelation, water and oil absorption, emulsification, foaming and protein solubility of raw and heat processed cowpea flour were determined. The effects of pH and NaCl concentration on some of these functional properties were also investigated. Protein solubility vs pH profile showed minimal solubility at pH 4. Water and oil absorption capacities of raw flour were 2.4 g/g and 2.9 g/g, respectively, while heat processed flour gave 3.6 g/g and 3.2 g/g, respectively. Addition of NaCl up to 0.4% improved the emulsification capacity of raw flour while a decrease was observed in the heat processed flour after 0.2%. Least gelation concentration of raw flour was found to be 16% and heat processed flour, 18%.